The present invention is directed to the use of a thick walled microporous hollow fiber membrane in a blood oxygenator.
Blood oygenators, as used herein, refers to the medical device that is used to maintain oxygen levels in the blood during surgery, for example heart by-pass surgery. A popular blood oxygenator uses microporous hollow fibers as the interface between the oxygen and the blood. See, for example, U.S. Pat. Nos. 5,489,413; 5,152,964; European Application Publication 507,722; 713,709.
In the use of these devices, xe2x80x98plasma leakagexe2x80x99 or xe2x80x98plasma breakthroughxe2x80x99 may be a problem. See: Tamari, Yehuda, et. al., xe2x80x9cThe Effect of High Pressure on Microporous Membrane Oxygenator Failurexe2x80x9d, Artificial Organs, Vol. 15, No. 1, pg. 15-22, (1991); and Montoya, J.P., et al., xe2x80x9cPlasma Leakage Through Microporous Membranes,xe2x80x9d ASAIO Journal, Vol. 38 pg. M399-405(1992). Plasma leakage is the movement of liquid through the micropores of the membrane from the blood side to the gas side of the device.
Accordingly, there is a need to improve the plasma breakthrough of microporous hollow fiber membranes.
The microporous hollow fiber membrane used herein are disclosed in U.S. Pat. No. 5,695,545. Other known hollow fibers are disclosed in U.S. Pat. Nos. 4,564,488; 4,530,809; 4,859,535; and 5,547,756.
The present invention is to a process for blood oxygenation using a microporous fiber membrane. The use of the hollow fiber allows improvements in plasma break through results. The oxygenator includes a housing and microporous membrane cartridge. The cartridge comprises a microporous hollow fiber membrane having a wall thickness greater than 30 microns and a bubble point of xe2x89xa7150 psig.